JP6524817B2 - Route control apparatus, route control system and route control method - Google Patents

Description

  The present invention relates to a route control device, a route control system, and a route control method.

  In computer networks, a path control device that controls communication paths is used. The path control device is, for example, a router or an L3 switch. The route control device has a routing table in which communication routes between information processing devices are registered. The route control device relays communication between information processing devices in accordance with the communication route registered in the routing table.

  In a computer network, communication paths between a path control device and an information processing device may be made redundant. By making the communication route redundant, the route control device switches the communication route with the information processing device to another communication route in which no failure occurs even when a failure occurs in part of the communication route. , It is possible to bypass the place where the failure occurred. The path control device detects a failure of the communication path by, for example, link down. As another method of detecting a fault, for example, the path control device detects a fault of the communication path by transmitting packets at predetermined intervals to confirm communication of the communication path (see, for example, Patent Document 1).

JP 9-8847 A

  By the way, there may be another communication device such as a switching hub between the location where the failure has occurred and the path control device. In such a case, the other communication apparatus suffers from a link down due to a failure. However, since another communication device intervenes between the route control device and the location where the failure has occurred, it can not detect the link down due to the failure. Therefore, the route control device can not detect a failure of the communication route due to the link down. As a result, the route control device can not switch the communication route to the bypass route bypassing the location where the failure occurs. Even in such a case, the route control device can detect a failure of the communication route according to the method of performing the connectivity check by the packets transmitted at predetermined intervals. However, when a packet for communication confirmation is transmitted at predetermined intervals, extra traffic different from communication between information processing apparatuses flows on the communication path.

  Therefore, an aspect of the disclosed technology is to provide a path control device capable of bypassing a fault on a communication path without flowing excess traffic.

One aspect of the disclosed technology is exemplified by the following path control device. The present route control device is a route control device that performs route control of a network in which communication routes to information processing devices are redundant, and includes a detection unit, a measurement unit, a connectivity check unit, and a control unit. The detection unit detects a first traffic directed to the information processing device via the route control device. The measuring unit measures an elapsed time from the detection. When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds the predetermined time which is determined that a failure has occurred in the communication path to the information processing apparatus, the communication confirming section communicates to the information processing apparatus. Send a request for confirmation and determine if there is a response to the request. The control unit switches the communication route to the information processing apparatus to the bypass route when it is determined that there is no response to the request.

  The routing control device can bypass a failure point on the communication route without flowing excess traffic.

FIG. 1 is a diagram illustrating an example of an internal network according to a first comparative example. FIG. 2 is a diagram showing an example of a routing table registered in the router. FIG. 3 is a diagram showing an example of the correspondence between the route information source and the Administrative Distance (AD) value. FIG. 4 is an example of a diagram for explaining the operation of VRRP, which is a protocol for making a router redundant. FIG. 5 is a diagram showing an example of an internal network in which a failure has occurred on a communication path between routers. FIG. 6 is a diagram showing an example of a communication path in the internal network when no failure occurs on the communication path. FIG. 7 is a diagram showing an example of an internal network in which a failure has occurred between a router and an L2 switch. FIG. 8 is a diagram illustrating an example of an internal network in which a failure occurs between L2 switches. FIG. 9 is a diagram illustrating an example of an internal network according to a second comparative example. FIG. 10 is a diagram illustrating an example of an internal network in which a failure occurs between L2 switches. FIG. 11 is a diagram illustrating an example of the internal network in which the link between the router and the L2 switch is linked down. FIG. 12 is a diagram illustrating an example of the internal network according to the first embodiment. FIG. 13 is a diagram illustrating an example of a hardware configuration of the information processing apparatus. FIG. 14 is a diagram illustrating an example of processing blocks of the router. FIG. 15 is a flow chart showing an example of the processing flow of the traffic monitoring unit that monitors downlink traffic. FIG. 16 is a diagram showing an example of destination information registered in the traffic database unit. FIG. 17 is a flow chart showing an example of the processing flow of the traffic monitoring unit that monitors uplink traffic. FIG. 18 is a flowchart illustrating an example of a process flow of the route bypass control unit. FIG. 19 is a diagram illustrating an example of a routing table to which static routes are added. FIG. 20 is a diagram illustrating an example of an internal network in which no failure occurs in the communication path from the router to the server. FIG. 21 is a diagram illustrating an example of an internal network in which upstream traffic from the server is not detected due to any cause. FIG. 22 is a diagram illustrating an example of an internal network in which a response to an ARP request has been confirmed. FIG. 23 is a diagram showing an example of the internal network in which the response of the ARP request is not confirmed. FIG. 24 is a diagram showing an example of the internal network after switching to the detour path. FIG. 25 is a diagram illustrating an example of an internal network in which a failure between L2 switches is recovered.

  A router according to an embodiment will be described below with reference to the drawings. The configurations of the embodiments shown below are illustrative, and the disclosed technology is not limited to the configurations of the embodiments.

First Comparative Example
FIG. 1 is a diagram illustrating an example of an internal network 500 according to a first comparative example. The internal network 500 includes routers 520a and 520b, L2 switches 530a and 530b, and a server 540. In the internal network 500, the communication route between the external network 510 and the server 540 is made redundant by the two routers 520a, 520b and the two L2 switches 530a, 530b. Hereinafter, in the present specification, the communication path is also referred to as a route.

  The external network 510 is a network outside the internal network 500, for example, the Internet. The routers 520 a and 520 b are path control devices that control communication paths of the internal network 500. The port P1 of the router 520a is connected to the L2 switch 530a. The port P2 of the router 520a is connected to the router 520b. The router 520 b is connected to the L2 switch 530 b. The routers 520a and 520b are collectively referred to as a router 520. The router 520 has a routing table which is a table in which routing information of communication routes is registered. The router 520 performs path control in accordance with the path information registered in the routing table. Path control is also referred to as routing. The router 520 is connected to the external network 510 as a gateway of the internal network 500. The router 520 detects a failure on the communication path by link down. The router 520 is configured to be redundant, for example, by a virtual router redundancy protocol (VRRP), which is a protocol used for router redundancy. Among the routers 520 in the redundant configuration, the router 520 a is a master router in an active state, and the router 520 b is a backup router in a standby state.

  The L2 switches 530a and 530b are switching hubs that relay computer network communications. The L2 switch 530a and the L2 switch 530b are connected to each other. The L2 switches 530a and 530b are collectively referred to as an L2 switch 530. The L2 switch 530 can perform path control by the MAC address. In the figure, the server connected to the L2 switch 530 is one server 540. However, the servers connected to the L2 switch 530 are not limited to one server 540. A plurality of servers may be connected to the L2 switch 530, or an information processing apparatus other than the server may be connected.

  The server 540 is an information processing apparatus. The server 540 provides various services in response to requests from client terminals (not shown) via an external network. The server 540 is, for example, a web server, a mail server or a name server. The server 540 has two network interface cards (NICs) of NIC # 1 and NIC # 2. The NIC # 1 is connected to the L2 switch 530a. The NIC # 2 is connected to the L2 switch 530b. The NIC of the server 540 is made redundant by the NIC # 1 and the NIC # 2. NIC # 1 is a standby NIC and NIC # 2 is an active NIC. Hereinafter, in the drawing, “A” is written to the NIC in the active state, and “S” is written to the NIC in the standby state. The number of servers 540 is not limited. One or more servers 540 may be provided.

  FIG. 2 is a diagram showing an example of the routing table. FIG. 2 shows an example of the execution result of the command for outputting the routing table in the router. The routing table illustrated in FIG. 2 differs from the routing table registered in the router 520 in the address system. The upper part of FIG. 2 describes a legend of the command execution result. In the lower four rows in FIG. 2, information on communication paths registered in the routing table is described one by one in each row. The information source of the information of the said communication path is described in the item of the left end among the information of a communication path. For example, the communication path shown in (2) is static when referring to the legend. That is, the communication path shown in (2) is set as a static route in the routing table. Of the communication path information, the IP address of the destination is described in the second item from the left.

FIG. 3 is a diagram showing an example of the correspondence between the route information source and the Administrative Distance (AD) value. The AD value is a value indicating the degree of reliability of the information source of the route. It is determined that the information source of the route with the smaller AD value has higher reliability. In the first column from the left of FIG. 3, information sources of route information are described. In the second column from the left in FIG. 3, AD values corresponding to the information sources described in the first column from the left are described. The third column from the left of FIG. 3 describes the information sources of communication path information. In the fourth column from the left in FIG. 3, AD values corresponding to the information sources described in the third column from the left are described. For example, when the information source of the route is OSPF, the AD value is 110.

The routing by the router will be described with reference to FIGS. 2 and 3. The router exchanges route information of communication routes registered in the routing table with various routing protocols with other route control devices including a router or the like. Routing protocols include Open Shortest Path First (OSPF), Internal Border Gateway Protocol (IBGP) and Routing Information Protocol (RIP). When a plurality of communication routes for the same destination are registered in the routing table, the router selects a communication route to be used in order of priority of the long guest match, the AD value, and the metric. In the selection by the long guest match, the communication path with the longest prefix length is selected among the plurality of communication paths. In the selection by the AD value, a route obtained from a more reliable source is selected. That is, in the selection by the AD value, a communication path with a lower AD value is selected. The metric is a value indicating the cost of the communication path. The metric is, for example, the number of routers passed to the destination. In the selection by metric, a communication path with lower metric is selected among the plurality of communication paths.

Referring to FIG. 2, it can be understood that there are two communication paths from the router to the information processing apparatus of the IP address 192.168.2.2, the communication path shown in (1) and the communication path shown in (2). The prefix value of the communication path indicated by (1) is 24 bits. Also, the prefix value of the communication path shown in (2) is 32 bits. Therefore, the communication path shown in (2) has a longer prefix length than the communication path shown in (1). Therefore, the router 520 selects the communication path indicated by (1) by the long guest match.

FIG. 4 is an example of a diagram for explaining the operation of VRRP, which is a protocol for making a router redundant. The VRRP will be described with reference to FIG. VRRP treats multiple routers as one virtual router. A virtual IP address and a virtual MAC address are assigned to the virtual router. In VRRP, router redundancy can be achieved by creating a virtual router including a plurality of routers. In FIG. 4, the router 520 a has the VRRP group set to 4 and the VRRP priority value set to 105. The router 520 b has a VRRP group of 4 and a VRRP priority value of 100. The VRRP virtual router is created by the routers 520a and 520b belonging to the same VRRP group. First, router 520a and router 52
0b exchanges advertisements including its own VRRP priority value. As a result, the router 520 a having a large VRRP priority value is the master router, and the router 520 b is the backup router. After that, the router 520a that has become the master router intermittently transmits advertisements to the router 520b that has become the backup router. The advertisement transmitted intermittently enables the router 520b, which is a backup router, to confirm the operation of the router 520a, which is a master router. Here, 3.30.5 as a virtual IP address and 0000.5E00.0104 as a virtual MAC address are allocated to the virtual router including the router 520a and the router 520b, for example.

  When an Address Resolution Protocol (ARP) request is issued from the server 540 to the IP address 3.3.3.1, the router 520a serving as the master router responds to the ARP request. Therefore, communication from the server 540 to the external network 510 passes through the router 520a.

  FIG. 5 is a diagram showing an example of the internal network 500 in which a failure has occurred on the communication path between the router 520a and the router 520b. Due to a failure on the communication path between the router 520a and the router 520b, the advertisement transmitted from the router 520a does not reach the router 520b. Therefore, the router 520b determines that there is a failure in the router 520a. As a result, the router 520b starts operating as a master router. The router 520b that has started operation as a master router transmits an advertisement to the router 520a. That is, in a state where a failure has occurred, both the router 520a and the router 520b transmit advertisements as a master router. However, while the failure is continuing, this advertisement does not reach the destination.

  When the failure recovers, the advertisements sent by router 520a and router 520b reach the destination. As a result, the router 520a in which the VRRP priority value is set to a large value is the master router, and the router 520b is the backup router. VRRP realizes router redundancy by the mechanism described above.

  FIG. 6 is a diagram showing an example of a communication path in the internal network 500 when no failure occurs on the communication path. The table described at the bottom of FIG. 6 is an example of the routing table registered in the router 520a. In this specification, traffic from the external network 510 to the internal network 500 is referred to as downstream traffic, and traffic from the internal network 500 to the external network 510 is referred to as upstream traffic.

The routing table illustrated in FIG.
As a communication path to 0, a communication path from port P1 of the router 520a to the L2 switch 530a and a communication path from the router 520a to the router 520b are registered. In these two communication paths, the prefix length of the destination is 24 bits. Therefore, the router 520a can not select a communication path in the long guest match. Therefore, the router 520a selects a communication route based on the AD value, which is a method of selecting a communication route having a higher priority next to the long guest match. Here, referring to the AD value whose example is shown in FIG. 3, the information source “Connected (corresponding to the connected interface in FIG. 3)” has a higher priority than “IBGP”. That is, the router 520a communicates with the server 540 through the communication path from the port P1 to the L2 switch 530a. Therefore, as shown in an example in FIG. 6, the downstream traffic reaches the NIC # 2 of the server 540 via the external network 510, the router 520a, the L2 switch 530a, and the L2 switch 530b. Also, uplink traffic reaches the external network 510 via the NIC # 2 of the server 540, the L2 switch 530b, the L2 switch 530a, and the router 520a.

  FIG. 7 is a diagram showing an example of the internal network 500 in which a failure has occurred between the router 520a and the L2 switch 530a. The router 520a detects the failure by link down with the L2 switch 530a. The router 520a that has detected the failure deletes from the routing table the communication route that passes through the L2 switch 530a from the port P1 that is the route in which the failure has occurred. As a result, the router 520a switches the communication path with the server 540 from the port P2 to a bypass path passing through the router 520b, which is a path obtained from the information source "IBGP". That is, as illustrated in FIG. 7, downlink traffic on the bypass route reaches the NIC # 2 of the server 540 via the external network 510, the router 520a, the router 520b, and the L2 switch 530b. Also, uplink traffic on the bypass route reaches the external network 510 via the NIC # 2 of the server 540, the L2 switch 530b, the router 520b, and the router 520a.

  FIG. 8 is a diagram showing an example of the internal network 500 in which a failure has occurred between the L2 switch 530a and the L2 switch 530b. The table described at the bottom of FIG. 8 is an example of the routing table registered in the router 520a. In this case, the connection between the router 520a and the L2 switch 530a is not linked down. Therefore, the router 520a can not detect this failure, and tries to relay the traffic from the external network 510 to the server 540 via the L2 switch 520a. Therefore, traffic from the external network 510 does not reach the server 540. In such a case, the administrator of the internal network 500 detects a failure between the L2 switch 530 a and the L2 switch 530 b by Simple Network Management Protocol (SNMP) or the like. The administrator of the internal network 500 that has detected the failure registers a detour path for bypassing the failure point in the routing table of the router 520a. That is, the administrator of the internal network 500 sets the communication path from the router 520a to the server 540 to be the NIC # 2 of the router 520a, the router 520b, the L2 switch 530b, and the server 540.

  In the first comparative example, the router 520 detects a failure on the communication path by link down. Therefore, when a communication device such as the L2 switch 530 is present between the router 520 and the point where the fault occurs, the router 520 may not be able to detect the fault. Therefore, the router 520 attempts to communicate with the server 540 by selecting the failed communication path. As a result, in the first comparative example, communication with the server 540 may not be possible.

Second Comparative Example
In the first comparative example, when a failure occurs between the L2 switch 530a and the L2 switch 530b, the administrator adds a bypass route for bypassing the failure point to the routing table. In the second comparative example, the failure point is bypassed by linking down the link between the router 520a and the L2 switch 530a. FIG. 9 is a diagram showing an example of an internal network 500 according to the second comparative example. The table described in the lower part of FIG. 9 is an example of the routing table registered in the router 520a. In FIG. 9, the server 540a and the server 540b are illustrated. The server 540a and the server 540b have two NICs # 1 and # 2, respectively. In the server 540a, the NIC # 1 is a standby NIC and the NIC # 2 is an active NIC. In the server 540a, the standby NIC # 1 is connected to the L2 switch 530a, and the active NIC # 2 is connected to the L2 switch 530b. In the server 540b, the NIC # 1 is an active NIC, and the NIC # 2 is a standby NIC. In the server 540b, the active NIC # 1 is connected to the L2 switch 530a, and the standby NIC # 2 is connected to the L2 switch 530b. That is, the communication path from the router 220a to the server 540a when no failure has occurred is in accordance with the routing table,
The router 220a, the L2 switch 530a, the L2 switch 530b, and the NIC # 2 of the server 540a. When no failure occurs, the communication path from the router 220a to the server 540b is the router # 220a, the L2 switch 530a, and the NIC # 1 of the server 540a.

  FIG. 10 is a diagram showing an example of the internal network 500 in which a failure has occurred between the L2 switch 530a and the L2 switch 530b. The table described at the bottom of FIG. 10 is an example of the routing table registered in the router 520a. The communication path between the router 520a and the server 540a includes between the failure occurrence point L2 switch 530a and L2 switch 530b. Therefore, communication between the router 520a and the server 540a is affected by the failure. However, the communication path between the router 520a and the server 540b does not include between the L2 switch 530a and the L2 switch 530b which are failure occurrence points. Therefore, communication between the router 520a and the server 540b is not affected by the failure.

  FIG. 11 is a diagram showing an example of the internal network 500 in which the link between the router 520a and the L2 switch 530a is down. The table described at the bottom of FIG. 11 is an example of a routing table registered in the router 520a. As the link between the router 520a and the L2 switch 530a is linked down, the communication addressed to the destination IP address 3.3.3.0/24 passes through the router 520b. That is, the communication path from the router 520a to the server 540a is the NIC # 2 of the router 520a, the router 520b, the L2 switch 530b, and the server 540a. The communication path from the router 520a to the server 540b is the NIC # 2 of the router 520a, the router 520b, the L2 switch 530b, and the server 540b. Here, the NIC # 2 of the server 540b is a NIC in a standby state. Therefore, in the server 540b, in order to enable communication with the router 520a, an operation of setting the NIC # 1 to the standby state and setting the NIC # 2 to the active state occurs. As a result, by linking down the link between the router 520a and the L2 switch 530a, work occurs for the server 540b not affected by the failure.

First Embodiment
In the first comparative example and the second comparative example, the router 520 detects a failure on the communication path by link down. In the first embodiment, a router that determines that a failure has occurred on a communication path when communication can not be detected for a predetermined time will be described. The same components as those in the first comparative example or the second comparative example will be assigned the same reference numerals and descriptions thereof will be omitted. The first embodiment will be described below with reference to the drawings.

FIG. 12 is a diagram showing an example of the internal network 300 according to the first embodiment. The table described in the lower part of FIG. 12 is an example of the routing table registered in the router 220a. In the routing table illustrated in FIG. 12, two communication paths are registered as communication paths to the destination IP address 3.3.3.0/24. One communication path is a router 220a whose information source is "Connected (corresponding to the connected interface in FIG. 3)".
Communication path relayed from the port P1 to the L2 switch 530a. The other communication path is a communication path relayed from the port P2 of the router 220a whose source is "IBGP" to the router 220b. Referring to the AD value illustrated in FIG. 3, “Connected” rather than “IBGP”
The priority is higher. Therefore, priority is given to the communication path relayed from the port P1 of the router 220a whose source is "Connected" to the L2 switch 530a. Internal network 300 differs from internal network 500 in that it has router 220a and router 220b. The internal network 300 is an example of “a network in which a communication path to an information processing apparatus is redundant”.

  The routers 220a and 220b are path control devices that control communication paths of the computer network. The routers 220a and 220b are collectively referred to as a router 220. The router 220 differs from the router 520 in that it detects a failure on a communication path by monitoring traffic on the communication path. The router 220 is an example of a “path control device”.

  FIG. 13 is a diagram illustrating an example of a hardware configuration of the information processing apparatus 100. The information processing apparatus 100 includes a processor 101, a main storage unit 102, an auxiliary storage unit 103, a communication unit 104, and a connection bus B1. The processor 101, the main storage unit 102, the auxiliary storage unit 103, and the communication unit 104 are mutually connected by a connection bus B1. The information processing apparatus 100 can be used as the router 220 and the server 540. The server 540 is an example of the “information processing apparatus”.

  In the information processing apparatus 100, the processor 101 expands a program stored in the auxiliary storage unit 103 into a work area of the main storage unit 102, and controls peripheral devices through the execution of the program. As a result, the information processing apparatus 100 can execute the processing that matches the predetermined purpose. The main storage unit 102 and the auxiliary storage unit 103 are recording media readable by the information processing apparatus 100.

  The main storage unit 102 is exemplified as a storage unit directly accessed by the processor 101. The main storage unit 102 includes Random Access Memory (RAM) and Read Only Memory (ROM).

  The auxiliary storage unit 103 stores various programs and various data in a recording medium so as to be readable and writable. The auxiliary storage unit 103 is also called an external storage device. The auxiliary storage unit 103 stores an operating system (OS), various programs, various tables, and the like. The OS includes a communication interface program that exchanges data with an external device or the like connected via the communication unit 104. The external device or the like includes, for example, another information processing device and an external storage device connected by a computer network or the like. The auxiliary storage unit 103 may be, for example, part of a cloud system that is a computer group on a network.

The auxiliary storage unit 103 may be, for example, an erasable programmable ROM (EPROM), a solid state drive (SSD), or a hard disk drive (hard disk).
Drive, HDD) and the like. The auxiliary storage unit 103 is, for example, a Compact Disc (CD) drive device, a Digital Versatile Disc (DVD) drive device, a Blu-ray (registered trademark) Disc (BD) drive device, or the like. Also, the auxiliary storage unit 103 may be provided by Network Attached Storage (NAS) or Storage Area Network (SAN).

  A recording medium readable by the information processing apparatus 100 is a recording that can store information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and read from the information processing apparatus 100. We say medium. Among such recording media, those removable from the information processing apparatus 100 include, for example, flexible disks, magneto-optical disks, CD-ROMs, CD-R / Ws, DVDs, Blu-ray disks, DAT, 8 mm tapes, flash memories, etc. Memory card etc. Further, as a recording medium fixed to the information processing apparatus 100, there is a hard disk, an SSD, a ROM or the like.

  The communication unit 104 is, for example, an interface with a communication path. The communication unit 104 communicates with an external device through a communication path.

  The information processing apparatus 100 may further include, for example, an input unit that receives an operation instruction or the like from a user or the like. As such an input unit, an input device such as a keyboard, a pointing device, a touch panel, an acceleration sensor or a voice input device can be exemplified.

The information processing apparatus 100 may include, for example, an output unit that outputs data processed by the processor 101 or data stored in the main storage unit 102. As such an output unit, an output device such as a Cathode Ray Tube (CRT) display, a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), an Electroluminescence (EL) panel, an organic EL panel or a printer can be exemplified.

<Processing Block of Router 220>
FIG. 14 is a diagram showing an example of processing blocks of the router 220. As shown in FIG. In FIG. 14, the traffic processing unit 301, the interface processing unit 302, the traffic monitoring unit 303, the traffic database unit 304, the timer unit 305, the route bypass control unit 306, the router setting information 307, the routing table 308, the routing control unit 309, and the ARP control. Each processing block of the part 310 is illustrated. For example, the processor 101 of the router 220 executes the computer program developed in the main storage unit 102 as each processing block in FIG. However, at least a part of any of the processing blocks in FIG. 14 may include a hardware circuit, a dedicated processor, or a digital signal processor (DSP).

  The traffic processing unit 301 includes a physical interface (denoted as IF in the drawing) and an interface processing unit 302. The physical interface corresponds to, for example, ports P1 and P2 in FIG. In the traffic processing unit 301, the processor 101 of the router 220 manages the physical interface as the interface processing unit 302. The interface processing unit 302 detects, for example, link up or link down of the physical interface.

  The processor 101 of the router 220 monitors the traffic passing through the router 220 as the traffic monitoring unit 303. When detecting the downstream traffic, the traffic monitoring unit 303 stores destination information indicating the server 540 which is the destination of the downstream traffic in the traffic database unit 304. When detecting the downlink traffic, the traffic monitoring unit 303 notifies the timer unit 305 of destination information indicating the server 540 that is the destination of the downlink traffic, and causes the timer unit 305 to start measuring the elapsed time. The traffic monitoring unit 303 detects uplink traffic from the server 540, and when destination information indicating the server 540 is registered in the traffic database unit 304, restarts measurement of elapsed time by the timer unit 305. The traffic monitoring unit 303 is an example of a “detection unit”. Downlink traffic is an example of “first traffic”. Uplink traffic is an example of “second traffic”.

  In the traffic database unit 304, destination information indicating the server 540 which is the destination of traffic is stored by the traffic monitoring unit 303. The destination information is information for specifying a server 540 as a destination, and is, for example, an IP address or a host name. The traffic database unit 304 is constructed, for example, on the main storage unit 102 or the auxiliary storage unit 103 of FIG. 13.

  The processor 101 of the router 220, as the timer unit 305, measures the elapsed time since the downlink traffic is detected. The elapsed time is measured for each server 540 indicated by the destination information included in the downlink traffic. The timer unit 305 is an example of the “measuring unit”.

  The processor 101 of the router 220, as the route bypass control unit 306, registers information on the communication route to the server 540 in the router setting information 307, and instructs the routing control unit 309 to change the communication route. The communication path change instruction is issued when the elapsed time measured by the timer unit 305 exceeds a predetermined time. The predetermined time is a time when it is determined that a failure has occurred in the communication path to the server 540. The predetermined time is stored, for example, in the main storage unit 102 or the auxiliary storage unit 103 of FIG. 13 when the router 220 is initially set. The route bypass control unit 306 is an example of a “control unit”.

  The processor 101 of the router 220 performs route control according to the information of the communication route registered in the routing table 308 as the routing control unit 309. The routing control unit 309 edits the routing table 308 in response to an instruction from the route bypass control unit 306. The routing control unit 309 edits the routing table 308 based on the information registered in the router setting information 307.

  The processor 101 of the router 220 performs an ARP request as the ARP control unit 310. The ARP request is triggered by an instruction from the route bypass control unit 306. The instruction from the route bypass control unit 306 includes the IP address of the server 540 which is the destination to make an ARP request. That is, the ARP control unit 310 makes an ARP request to the server 540 instructed by the route bypass control unit 306. Also, the ARP request 310 notifies the route bypass control unit 306 of the presence or absence of a response to the ARP request from the server 540. The ARP control unit is an example of the “communication check unit”. The ARP request is an example of the “communication confirmation request”.

  FIG. 15 is a flowchart showing an example of a process flow of the traffic monitoring unit 303 that monitors downlink traffic. The process of the traffic monitoring unit 303 that monitors downlink traffic will be described with reference to FIG.

  At T1, the traffic monitoring unit 303 determines whether downlink traffic has flowed into the router 220. When the downlink traffic flows into the router 220, the traffic monitoring unit 303 advances the process to T2. When the downlink traffic does not flow into the router 220, the traffic monitoring unit 303 repeats the determination of T1.

  At T2, the traffic monitoring unit 303 checks whether or not the IP address specified as the destination of the downstream traffic is registered in the traffic database unit 304. When the IP address designated as the destination of the downlink traffic is registered in the traffic database unit 304, the traffic monitoring unit 303 advances the process to T1. If the IP address designated as the destination of the downlink traffic is not registered in the traffic database unit 304, the traffic monitoring unit 303 advances the process to T3.

FIG. 16 is a diagram showing an example of destination information registered in the traffic database unit 304. As shown in FIG. An IP address is registered in the traffic database unit 304 as destination information of downlink traffic. In FIG. 16, IP address: 3.3.3.2 as destination information.
And the IP address 3.3.3.3 is registered.

  Returning to FIG. 15, at T3, the traffic monitoring unit 303 registers the IP address designated as the destination of the downlink traffic in the traffic database unit 304. At T4, the traffic monitoring unit 303 starts measuring the elapsed time by the timer unit 305.

FIG. 17 is a flowchart showing an example of a process flow of the traffic monitoring unit 303 that monitors uplink traffic. The process of the traffic monitoring unit 303 that monitors uplink traffic will be described with reference to FIG.

  At T11, the traffic monitoring unit 303 determines whether or not upstream traffic has flowed into the router 220. When the upstream traffic flows into the router 220, the traffic monitoring unit 303 advances the process to T12. If uplink traffic has not flowed into the router 220, the traffic monitoring unit 303 repeats the determination of T11.

  At T12, the traffic monitoring unit 303 confirms whether or not the IP address specified as the transmission source of the uplink traffic is registered in the traffic database unit 304. When the IP address designated as the transmission source of the uplink traffic is registered in the traffic database unit 304, the traffic monitoring unit 303 advances the process to T13. If the IP address designated as the transmission source of the uplink traffic is not registered in the traffic database unit 304, the traffic monitoring unit 303 advances the process to T11.

  At T13, the traffic monitoring unit 303 restarts the measurement of the elapsed time by the timer unit 305. That is, the traffic monitoring unit 303 causes the timer unit 305 to reset the measured elapsed time to 0 once, and starts measuring the elapsed time again.

  FIG. 18 is a flowchart showing an example of the process flow of the route bypass control unit 306. The process of the route bypass control unit 306 will be described with reference to FIG.

  At T31, the route bypass control unit 306 checks whether the elapsed time measured by the timer unit 305 for each destination IP address is equal to or less than a predetermined time. If the elapsed time measured by the timer unit 305 is equal to or longer than the predetermined time, the path bypass control unit 306 advances the process to T32. If the elapsed time measured by the timer unit 305 is less than the predetermined time, the path bypass control unit 306 repeats the determination of T31.

  At T32, the route bypass control unit 306 instructs the ARP control unit 310 to transmit an ARP request. The ARP control unit 310 makes an ARP request in accordance with an instruction from the route bypass control unit 306. The ARP request is issued to the destination IP address whose elapsed time measured by the timer unit 305 exceeds a predetermined time. In other words, an ARP request is made to a destination IP address that is suspected of having a failure in the communication path with the router 220a.

  At T33, the ARP control unit 310 confirms the presence or absence of a response to the ARP request. The ARP control unit 310 notifies the route bypass control unit 306 of the confirmation result. If the response to the ARP request is confirmed, the route bypass control unit 306 advances the process to T37. If the response to the ARP request is not confirmed, the route bypass control unit 306 advances the process to T34.

  At T34, the route bypass control unit 306 registers the IP address of the destination for which the response to the ARP request has not been confirmed in the router setting information 307, and instructs the routing control unit 309 to change the setting in the routing table 308. The routing control unit 309 changes the routing table 308 in accordance with the information registered in the router setting information 307. Specifically, the routing control unit 309 registers the IP address registered in the router setting information in the routing table 308 as a static route.

FIG. 19 is a diagram illustrating an example of a routing table to which static routes are added. In FIG. 19, as a static route to the server 540, a communication path for transferring traffic to the destination IP address 3.3.3.3/32 to the router 220b is added. In the routing table illustrated in FIG. 19, a plurality of communication paths to the server 540 having the IP address 3.3.3.3 are registered. Here, the router 220a selects the added communication route as a bypass route to the server 540 according to the long guest match.

  Referring back to FIG. 18, in T35, the route bypass control unit 306 determines whether or not the measurement of the elapsed time by the timer unit 305 has been restarted. If the measurement of the elapsed time by the timer unit 305 is restarted, the path bypass control unit 306 advances the process to T36. When the measurement of the elapsed time by the timer unit 305 is not restarted, the path bypass control unit 306 repeats the process of T35.

  At T36, the route bypass control unit 306 deletes the information of the IP address added at T34 from the router setting information 307, and instructs the routing control unit 309 to change the setting in the routing table 308. The routing control unit 309 changes the routing table 308 in accordance with the information registered in the router setting information 307. Specifically, the routing control unit 309 deletes the IP address deleted from the router setting information from the routing table 308.

  At T37, the route bypass control unit 306 restarts the measurement of the elapsed time by the timer unit 305. That is, the route bypass control unit 306 causes the timer unit 305 to reset the measured elapsed time to 0 once, and starts measuring the elapsed time again.

  Based on what has been described above, switching of the communication path to the detour path by the router 220a will be described.

  FIG. 20 is a diagram showing an example of the internal network 300 in which no failure occurs in the communication path from the router 220 a to the server 540. The table described at the bottom of FIG. 20 is an example of the routing table registered in the router 220a. The router 220 a detects the downstream traffic to the server 540 by the traffic monitoring unit 303. The traffic monitoring unit 303 that has detected the downlink traffic instructs the timer unit 305 to start measuring the elapsed time. The traffic monitoring unit 303 that has detected the upstream traffic from the server 540 instructs the timer unit 305 to restart the elapsed time measurement.

  FIG. 21 is a diagram showing an example of the internal network 300 in which upstream traffic from the server 540 is not detected due to any cause. The table described in the lower part of FIG. 21 is an example of the routing table registered in the router 220a. In FIG. 21, the traffic monitoring unit 303 does not detect the upstream traffic from the server 540 even if the elapsed time measured by the timer unit 305 exceeds the predetermined time. In such a case, a failure may occur on the communication path between the router 220a and the server 540. Therefore, the route bypass control unit 306 of the router 220 a instructs the ARP control unit 310 to transmit an ARP request to the server 540.

  FIG. 22 is a diagram showing an example of the internal network 300 in which the response to the ARP request has been confirmed. The table described in the lower part of FIG. 22 is an example of the routing table registered in the router 220a. In FIG. 22, the ARP request transmitted from the router 220 a reaches the server 540. The server 540 that has received the ARP request transmits a response to the ARP request to the router 220a. By receiving a response to the ARP request from the server 540, the router 220a can determine that no failure has occurred on the communication path from the router 220a to the server 540.

FIG. 23 is a diagram showing an example of the internal network 300 in which the response of the ARP request is not confirmed. In FIG. 23, a fault has occurred between the L2 switch 530a and the L2 switch 530b. The ARP request from the router 220a does not reach the server 540 due to the effect of the failure. The router 220 a can determine that a failure has occurred on the communication path from the router 220 a to the server 540 by not receiving a response to the ARP request from the server 540.

  FIG. 24 is a diagram showing an example of the internal network 300 after being switched to the detour path. The routing control unit 309 adds information of the static route to the server 540 to the routing table 308 based on the information registered in the router setting information 307 by the route bypass control unit 306. As a result, the communication path from the router 220a to the server 540 becomes a detour path for bypassing the failure point.

  FIG. 25 is a diagram showing an example of the internal network 300 in which the failure between the L2 switch 530a and the L2 switch 530b is recovered. By the failure recovery, uplink traffic from the server 540 is detected at the port P1 of the router 220a. When traffic from the server 540 is detected at the port P1, the traffic monitoring unit 303 restarts the measurement of the elapsed time by the timer unit 305. The route bypass control unit 306 monitors the timer unit 305 to detect that the measurement of the elapsed time has been restarted. The route detour control unit 306 that has detected the restart of the elapsed time measurement deletes the information on the static route added as the detour route from the router setting information 307, and instructs the routing control unit 309 to change the routing. The routing control unit 309 deletes the information of the static route registered as the bypass route from the routing table 308 based on the information registered in the router setting information 307. As a result, the communication path between the router 220a and the server 540 returns to the state illustrated in FIG.

  In the first embodiment, when the router 220 detects the downstream traffic to the server 540 and the traffic from the server 540 is not detected within a predetermined time, the communication path between the router 220 and the server 540 It was determined that there was a possibility that a failure occurred at the top. That is, the router 220 does not have to transmit packets at predetermined intervals for communication confirmation with the server 540. As a result, according to the first embodiment, it is possible to suppress the generation of extra traffic for the communication check.

  In the first embodiment, the router 220 transmits an ARP request to the server 540 when it determines that there is a possibility that a failure has occurred on the communication path with the server 540. The router 220 determines whether a failure occurs on the communication path between the router 220 and the server 540 based on the presence or absence of the response to the ARP request. As a result, according to the first embodiment, it is possible to suppress the switching to the detour path when there is no failure on the communication path and the server 540 does not transmit traffic. Also, the ARP request is made when it is determined that there is a possibility that a failure has occurred on the communication path with the server 540. Therefore, according to the first embodiment, the generation of extra traffic for communication confirmation is suppressed as compared to the case where packets are transmitted at predetermined intervals for communication confirmation.

  In the first embodiment, an ARP request is used to confirm the communication with the server 540. Therefore, according to the first embodiment, even when the MAC address of the server 540 is changed due to NIC exchange or the like, the response from the server 540 can be received.

  In the first embodiment, an ARP request is issued to confirm the communication with the server 540. However, the communication confirmation with the server 540 is not limited to the ARP request. Various commands for requesting a response from the server 540 can be employed to confirm the communication with the server 540. Examples of commands that request the server 540 for a response include a ping command, a traceroute command, and a telnet command.

  In the first embodiment, when a failure occurs on the communication route, the communication route to the server affected by the failure is changed to the bypass route. Therefore, according to the first embodiment, the influence of the change to the bypass route to the server not affected by the failure is suppressed.

  In the first embodiment, the traffic processing unit 301, the interface processing unit 302, the traffic monitoring unit 303, the traffic database unit 304, the timer unit 305, the route bypass control unit 306, the router setting information 307, the routing table 308, the routing control unit 309, The router 220 having each processing block of the ARP control unit 310 performs path control. However, the router 220 is not limited to such a form. The router 220 may, for example, execute each processing block by a different information processing apparatus. In this case, the information processing apparatuses that execute the respective processing blocks may be connected to each other by a network and operated in cooperation with each other. Information processing apparatuses that execute processing blocks and cooperate with each other are an example of a “path control system”.

<Others>
Further, the following appendices will be disclosed regarding the embodiment described above.
(Supplementary Note 1)
A route control device that performs route control of a network in which a communication route to an information processing device is redundant,
A detection unit that detects a first traffic directed to the information processing apparatus via the route control apparatus;
A measurement unit that measures an elapsed time from the detection;
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus Sending a request to perform and determining whether there is a response to the request,
And a control unit configured to switch a communication route to the information processing apparatus to a bypass route when it is determined that there is no response to the request.
Routing controller.
(Supplementary Note 2)
There are multiple information processing devices in the network,
The measurement unit measures an elapsed time for each information processing apparatus indicated by destination information included in the first traffic.
The routing control device according to appendix 1.
(Supplementary Note 3)
The measuring unit initializes the elapsed time when the second traffic is detected, and restarts the measurement of the elapsed time.
The routing control device according to Appendix 1 or 2.
(Supplementary Note 4)
The communication confirmation request is an ARP request,
The routing control device according to any one of appendices 1 to 3.
(Supplementary Note 5)
A route control system for performing route control of a network in which a communication route to an information processing apparatus is redundant,
A detection device that detects a first traffic toward the information processing device via the route control device;
A measuring device that measures an elapsed time from the detection;
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus A communication confirmation apparatus for transmitting a request to perform the request and determining whether there is a response to the request;
And a control device for switching a communication route to the information processing apparatus to a bypass route when it is determined that there is no response to the request.
Routing control system.
(Supplementary Note 6)
There are multiple information processing devices in the network,
The measurement unit measures an elapsed time for each information processing apparatus indicated by destination information included in the first traffic.
The routing control system according to appendix 5.
(Appendix 7)
The measuring device initializes the elapsed time when the second traffic is detected, and restarts the measurement of the elapsed time.
The routing control system according to Appendix 5 or 6.
(Supplementary Note 8)
The communication confirmation request is an ARP request,
The routing control system according to any one of appendices 5 to 7.
(Appendix 9)
A route control method executed by a route control device performing route control of a network in which communication routes to information processing devices are redundant,
Detecting a first traffic going to the information processing apparatus via the route control apparatus;
Measure the elapsed time from the detection,
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus Send a request to determine the presence or absence of a response to the request,
When it is determined that there is no response to the request, the communication route to the information processing apparatus is switched to a bypass route.
Route control method.
(Supplementary Note 10)
There are multiple information processing devices in the network,
The measurement includes measurement of elapsed time for each information processing apparatus indicated by destination information included in the first traffic.
The route control method according to appendix 9.
(Supplementary Note 11)
The measurement includes a process of initializing the elapsed time when the second traffic is detected and resuming measurement of the elapsed time.
The route control method according to appendix 9 or 10.
(Supplementary Note 12)
The communication confirmation data is an ARP request,
The route control method according to any one of appendices 9 to 11.

301: Traffic processing unit 302: Interface processing unit 303: Traffic monitoring unit 304: Traffic database unit 305: Timer unit 306: Route bypass control unit 307: Router setting information 308 ... routing table 309 ... routing control unit 310 ... ARP control unit 300, 500 ... internal network 510 ... external network 220, 220a, 220b, 520, 520a, 520b ... router 530, 530a, 530b ... L2 switch 540 ... server

Claims (6)

A route control device that performs route control of a network in which a communication route to an information processing device is redundant,
A detection unit that detects a first traffic directed to the information processing apparatus via the route control apparatus;
A measurement unit that measures an elapsed time from the detection;
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus Sending a request to perform and determining whether there is a response to the request,
And a control unit configured to switch a communication route to the information processing apparatus to a bypass route when it is determined that there is no response to the request.
Routing controller. There are multiple information processing devices in the network,
The measurement unit measures the elapsed time for each information processing apparatus indicated by destination information included in the first traffic.
The routing control device according to claim 1. The measuring unit initializes the elapsed time when the second traffic is detected, and restarts the measurement of the elapsed time.
The routing control device according to claim 1 or 2. The communication confirmation request is an ARP (Address Resolution Protocol) request,
The path control device according to any one of claims 1 to 3. A route control system for performing route control of a network in which a communication route to an information processing apparatus is redundant,
A detection device for detecting a first traffic directed to the information processing device via the route control system ;
A measuring device that measures an elapsed time from the detection;
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus A communication confirmation apparatus for transmitting a request to perform the request and determining whether there is a response to the request;
And a control device for switching a communication route to the information processing apparatus to a bypass route when it is determined that there is no response to the request.
Routing control system. A route control method executed by a route control device performing route control of a network in which communication routes to information processing devices are redundant,
Detecting a first traffic going to the information processing apparatus via the route control apparatus;
Measure the elapsed time from the detection,
When the second traffic from the information processing apparatus is not detected until the elapsed time exceeds a predetermined time determined that a failure occurs in the communication path to the information processing apparatus, the communication check to the information processing apparatus Send a request to determine the presence or absence of a response to the request,
When it is determined that there is no response to the request, the communication route to the information processing apparatus is switched to a bypass route.
Route control method.

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